A COVID surge fueled by the emergence of the highly transmissible although less lethal omicron variant in early January led three of the state's largest districts to shift into remote learning.

Officials in Minneapolis, Osseo and Rochester cited educator absences as everyone from teachers to bus drivers either fell ill or had to care for sick family members.

But several other districts largely have kept classrooms open. A survey of isolation, masking and remote-learning policies across the state's largest districts demonstrates how school decision-makers across Minnesota are approaching a reality in which staffing shortages, rather than COVID-19 infections, are an increasingly important factor in whether they can offer in-person instruction.

Across the 10 districts with the largest share of Minnesota's K-12 pupils — which together educate one in four of the state's public school students — officials say they keep an eye on daily staff absences in order to predict whether they must move into distance learning.

From Anoka-Hennepin to South Washington County, various staffers, from school principals to math support specialists and even central office administrators, have filled in when substitutes are in short supply. In the Rosemount-Apple Valley-Eagan district, administrators have become used to monitoring absences among bus drivers to determine whether they'll be driving a route that day.

"That does get exhausting, literally, when you show up everyday and you say, 'Okay, we've got to fill 20 absences today, who can drive a route?'" district spokesperson Tony Taschner said.

In the Wayzata district, individual classrooms have moved into remote learning while avoiding any full-school closures, spokesperson Amy Parnell said. In the South Washington County district, officials have put 11 classes in virtual learning since students returned after the winter break, spokesperson Pepe Barton said.

The Anoka-Hennepin district averaged about 330 absences among teachers last week, according to figures provided to the Star Tribune. Of those, only about 93 went unfilled on any given day.

"Staff absences are high but are decreasing, and the ability to provide substitute employees is improving," spokesperson Jim Skelly said.

Only one district that hasn't shifted into virtual learning has told families what metrics would prompt the move.

Officials in St. Paul send a note to parents if at least 25% of a school's teachers are absent on a given day. Those emails will indicate it's possible the building will move into remote learning if that rate is projected to last more than three consecutive days.

Officials in Elk River declined to provide details on the metrics that dictate whether a school moves into remote learning, saying only, "There are many factors in play for that decision."

"I can safely say that we are working closely with local public health officials and other superintendents to explore and evaluate various rubrics," spokesperson Cory Franson said.

Mask policies vary

All but one district require nearly everyone older than 2 to wear masks indoors regardless of vaccination status. The Elk River district recommends, but does not require, students and teachers to wear masks in class.

And in Anoka-Hennepin, students in elementary school and in sixth grade must mask up if the two counties log 15 or more infections per 10,000 residents over a seven-day period.

The Rosemount-Apple Valley-Eagan School district has recorded 700 student infections and 107 positive cases among staff since the start of the school year, according to its COVID-19 dashboard. That's fewer than 48 total infections per week since the start of the academic year.

Taschner said officials credit the masking policy for limiting transmission of COVID-19 in classrooms.

"That's one of the biggest things we credit for being able to stay in-person," he said.

The Anoka-Hennepin school board on Monday will consider a new masking policy, unique among its peer districts. That policy would have individual schools adopt universal masking if Anoka and Hennepin counties log more than 50 infections per 10,000 residents and student absences are more than double the historic average.

In January, an absence rate of 8% or more would trigger the mask mandate in elementary schools. In middle schools, it's 11% and in high schools it's 13%, according to a district presentation.

The state's largest districts almost uniformly hew to isolation guidelines the national Centers for Disease Control and Prevention released in late December. Rather than notify families about individual cases in schools, districts now publish weekly digests that aggregate a weeks' worth of infection tallies.

And instead of isolating for 10 days after exposure, students and staff must stay home for five days if they begin to show symptoms or test positive for COVID-19, according to each district's Safe Learning Plan.

Every district's policy indicates that students may return to classrooms on the sixth day but must wear a mask until the 10th day. Pupils who can't wear a mask or refuse to do so can't return to a school building for 10 days after they show symptoms or test positive.

Rosemount-Apple Valley-Eagan's Taschner said staff absences, rather than community spread of COVID-19, now play a dominant role in conversations over remote learning.

It's a marked shift from the beginning of the pandemic, when public health officials knew less about COVID-19 and its spread and school safety protocols largely were meant to limit contact between people.

"It's not about keeping people away from each other and separated because the reality, at least until recently, is that school is one of the few places where people are wearing masks on a consistent basis," Taschner said.